Helmet rib



FIG. 1 is a perspective view of a helmet rib showing our new design;

FIG. 2 is a left side view thereof, the right side being a mirror imagethereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The details shown in broken lines form no part of the claimed design.

CLAIM The ornamental design for a helmet rib, as shown and described.